Hm, I've put a bit of thought into it and come up with my conclusion...
...It's a load of rubbish. :rofl:
It's mechanically equivalent to a couple of simple 3-element epicyclic gearsets. The difference here is rather than driving one component of the gearset, taking power from the second, and locking the third to one or other member or allowing it to freerun (this is actually how automatic transmissions work; you have multiples of these gearsets controlled with brake bands and one-way clutches, all actuated by a fiendishly complicated electrohydraulic control system), you are effectively powering two elements and using the third as your output.
The issue here is that you can't just throw all the power on one input (say, from your engine) and use a dinky little motor as your control, like the video seemed to suggest; in truth, the term "control" is arbitrary and your output speed AND TORQUE just comes from the relation of both inputs together. In other words, your "control" motor needs to be on the order of as powerful as your "input" motor.
Okay... this suggests a possible component of a hybrid drive, doesn't it - your petrol or diesel engine as one input, and the electric motor/generator set as the other?
Ahh yes! The "Hybrid Synergy Drive"
on the Prius is exactly that!
Nothing new, and I'd imagine nothing notably patentable.